Automatic test equipment is generally used to test semiconductor devices and integrated circuit (IC) elements, such as memory or logic, for manufacturing defects. Manufacturers of automatic test equipment (ATE) offer test systems to address the increasingly complex task of testing advanced ICs. However, many commercially available ATE systems are complex, proprietary, not easily flexible to meet changing test conditions, and often require additional heat removal systems and typically cost several million dollars that make them unattractive for use in a cost driven manufacturing environment. Recently, many semiconductor manufacturers and some ATE suppliers have introduced low cost test systems such as the TI proprietary or other very low cost tester (VLCT). The
VLCT system may be used as a standalone test system and/or used in combination with a conventional ATE system (this is called “Multi Path Testing”). The VLCT systems typically provide lower test costs and are more flexible in meeting the changing test conditions, making them more attractive in the cost driven manufacturing environment.
Testing devices during production generally requires an appropriate tester to test an IC chip. During production of an integrated processor, various tests may be performed. A test system allows a test assembly to interface with a chip using an interface apparatus.
A conventional programmable electronic circuit test system tests a “device under test” and commonly referred to as a “DUT.” FIG. 1 illustrates a diagram of a conventional test system 10 for testing a DUT 12. The test system 10 includes a tester 14 that is operable to communicate test signals to the DUT through a test head 16 via one or more electrical couplers 18 such as conductors, cables, lines pins, links, traces, and/or busses. The tester 14 may have various electronic test and measurement instruments, such as AC and DC electrical signal generators for applying electrical signals through digital and/or analog channels to a DUT on the test head 16. Tester 14 is also has capabilities to receive and analyze data from tests performed on a DUT 12.
For every IC that is designed and manufactured, test hardware called a test interface board or “load board” 20 is built for production tests. FIG. 1 illustrates how a typical tester 14 interfaces to DUT 12 through load board 20 that is attached to the test head 16. The DUT 12 is mounted onto the load board 20 via a socket. Configurations of a load board can vary depending on the type, size, and quantity of DUTS being tested. A typical load board 20 is a printed circuit board (PCB) that may be up to about 5 mm thick.
Tester 14 communicates instructions and test programs to the test head 16, which applies analog test signals to DFT or other architecture of DUT 12 through load board 20 using connectors between the DUT 12 I/O (Input/Output) ports and load board 20. Load board 20 may comprise one or more RF connectors, where each connector is operable to communicate an RF test signal to DUT 12 and also may include high-speed test signals through hard-wired connections. DUT 12 receives analog test signals from the load board 20, processes the signals according to a test procedure, and transmits the processed test signals back to the load board 20, which transmits the test data through the test head 16 and back to the tester 14 for further analysis by tester 14.
To increase the mass production of a DUT 12, the test system 10 can be programmed to perform the tests on multiple DUTs on a load board 20 in parallel. In this way, multiple DUTs can be tested rapidly and simultaneously. To automatically load and unload DUT 12 to and from sockets on a load board 20, a robotic handling machine called a handler (not shown) can be included with a test system 10. The handler also sorts the failing DUTs from passing DUTs after a test is performed.
Many commercially available, advanced, multi-function test systems are often very complex, bulky, require additional heat removal systems and typically cost several million dollars. Some of the lower cost test systems may offer more flexibility and may be more affordable but may be limited by their performance and capacity. For example, some VLCT systems may have a limited data throughput for testing and may include a limited number of input/output (I/O) channels available for testing. Other limitations may include processing speed of the computers and test instruments and limited processing capacity (e.g., MIPS, DSP, Data transfer rate or memory) in a tester. Some of these limitations may result in increasing the time and therefore reducing the efficiency to test each IC device. The additional time needed for testing each device is magnified at the manufacturing process level when a up to millions of chips need to be tested. As a result, some of the limitations of the VLCT systems may inadvertently slow down the production rate and may contribute to an overall increase in the cost of testing.
Since VLCT systems have limitations on performance and capacity that may negatively impact the production rate for manufacturing a device, the alternative of purchase new VLCT systems for different types of devices can be cost prohibitive, as each new system costs hundreds of thousands of dollars. Further, if a new type of DUT is to be tested, or if multiple DUTs need to be tested to increase the production capacity, the old load board must be replaced with a new board compatible with the different DUT, which increases costs. There is a need for a low-cost, fast, and flexible solution for performing tests of new devices.